Conventionally, in the process of manufacturing an optical fiber, an ultraviolet-curable coating agent is coated on the surface of the optical fiber in order to protect the surface of the drawn optical fiber and to maintain the strength of the optical fiber. Such a coating agent is coated in an uncured state by a coating device and cured by a light irradiation device from which ultraviolet light radiates (for example, Patent Document 1).
Patent Document 1 describes a device for curing a coating material by allowing a drawn optical fiber coated with the coating material (coating agent) to pass through a curing chamber having an elliptic housing. The interior of the elliptic housing is provided with an elliptical mirror and a quartz halogen lamp extended in parallel to the path of the optical fiber and constituted to respectively dispose the quartz halogen lamp and the optical fiber at the first focal position and the second focal position of the elliptical mirror so that ultraviolet light to radiate from the quartz halogen lamp reliably hits the outer circumference of the optical fiber.